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linux_dsm_epyc7002/net/netlink/af_netlink.c
Ben Pfaff ac30ef832e netlink: Fix handling of error from netlink_dump(). 
netlink_dump() returns a negative errno value on error.  Until now,
netlink_recvmsg() directly recorded that negative value in sk->sk_err, but
that's wrong since sk_err takes positive errno values.  (This manifests as
userspace receiving a positive return value from the recv() system call,
falsely indicating success.) This bug was introduced in the commit that
started checking the netlink_dump() return value, commit b44d211 (netlink:
handle errors from netlink_dump()).

Multithreaded Netlink dumps are one way to trigger this behavior in
practice, as described in the commit message for the userspace workaround
posted here:
    http://openvswitch.org/pipermail/dev/2014-June/042339.html

This commit also fixes the same bug in netlink_poll(), introduced in commit
cd1df525d (netlink: add flow control for memory mapped I/O).

Signed-off-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-09 14:33:47 -07:00

3232 lines
74 KiB
C
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/*
* NETLINK Kernel-user communication protocol.
*
* Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
* Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
* Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
* added netlink_proto_exit
* Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
* use nlk_sk, as sk->protinfo is on a diet 8)
* Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
* - inc module use count of module that owns
* the kernel socket in case userspace opens
* socket of same protocol
* - remove all module support, since netlink is
* mandatory if CONFIG_NET=y these days
*/
#include <linux/module.h>
#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/socket.h>
#include <linux/un.h>
#include <linux/fcntl.h>
#include <linux/termios.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/notifier.h>
#include <linux/security.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/random.h>
#include <linux/bitops.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/audit.h>
#include <linux/mutex.h>
#include <linux/vmalloc.h>
#include <linux/if_arp.h>
#include <asm/cacheflush.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/scm.h>
#include <net/netlink.h>
#include "af_netlink.h"
struct listeners {
struct rcu_head rcu;
unsigned long masks[0];
};
/* state bits */
#define NETLINK_CONGESTED 0x0
/* flags */
#define NETLINK_KERNEL_SOCKET 0x1
#define NETLINK_RECV_PKTINFO 0x2
#define NETLINK_BROADCAST_SEND_ERROR 0x4
#define NETLINK_RECV_NO_ENOBUFS 0x8
static inline int netlink_is_kernel(struct sock *sk)
{
return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
}
struct netlink_table *nl_table;
EXPORT_SYMBOL_GPL(nl_table);
static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
static int netlink_dump(struct sock *sk);
static void netlink_skb_destructor(struct sk_buff *skb);
DEFINE_RWLOCK(nl_table_lock);
EXPORT_SYMBOL_GPL(nl_table_lock);
static atomic_t nl_table_users = ATOMIC_INIT(0);
#define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
static ATOMIC_NOTIFIER_HEAD(netlink_chain);
static DEFINE_SPINLOCK(netlink_tap_lock);
static struct list_head netlink_tap_all __read_mostly;
static inline u32 netlink_group_mask(u32 group)
{
return group ? 1 << (group - 1) : 0;
}
static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u32 portid)
{
return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask];
}
int netlink_add_tap(struct netlink_tap *nt)
{
if (unlikely(nt->dev->type != ARPHRD_NETLINK))
return -EINVAL;
spin_lock(&netlink_tap_lock);
list_add_rcu(&nt->list, &netlink_tap_all);
spin_unlock(&netlink_tap_lock);
if (nt->module)
__module_get(nt->module);
return 0;
}
EXPORT_SYMBOL_GPL(netlink_add_tap);
static int __netlink_remove_tap(struct netlink_tap *nt)
{
bool found = false;
struct netlink_tap *tmp;
spin_lock(&netlink_tap_lock);
list_for_each_entry(tmp, &netlink_tap_all, list) {
if (nt == tmp) {
list_del_rcu(&nt->list);
found = true;
goto out;
}
}
pr_warn("__netlink_remove_tap: %p not found\n", nt);
out:
spin_unlock(&netlink_tap_lock);
if (found && nt->module)
module_put(nt->module);
return found ? 0 : -ENODEV;
}
int netlink_remove_tap(struct netlink_tap *nt)
{
int ret;
ret = __netlink_remove_tap(nt);
synchronize_net();
return ret;
}
EXPORT_SYMBOL_GPL(netlink_remove_tap);
static bool netlink_filter_tap(const struct sk_buff *skb)
{
struct sock *sk = skb->sk;
bool pass = false;
/* We take the more conservative approach and
* whitelist socket protocols that may pass.
*/
switch (sk->sk_protocol) {
case NETLINK_ROUTE:
case NETLINK_USERSOCK:
case NETLINK_SOCK_DIAG:
case NETLINK_NFLOG:
case NETLINK_XFRM:
case NETLINK_FIB_LOOKUP:
case NETLINK_NETFILTER:
case NETLINK_GENERIC:
pass = true;
break;
}
return pass;
}
static int __netlink_deliver_tap_skb(struct sk_buff *skb,
struct net_device *dev)
{
struct sk_buff *nskb;
struct sock *sk = skb->sk;
int ret = -ENOMEM;
dev_hold(dev);
nskb = skb_clone(skb, GFP_ATOMIC);
if (nskb) {
nskb->dev = dev;
nskb->protocol = htons((u16) sk->sk_protocol);
nskb->pkt_type = netlink_is_kernel(sk) ?
PACKET_KERNEL : PACKET_USER;
ret = dev_queue_xmit(nskb);
if (unlikely(ret > 0))
ret = net_xmit_errno(ret);
}
dev_put(dev);
return ret;
}
static void __netlink_deliver_tap(struct sk_buff *skb)
{
int ret;
struct netlink_tap *tmp;
if (!netlink_filter_tap(skb))
return;
list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
ret = __netlink_deliver_tap_skb(skb, tmp->dev);
if (unlikely(ret))
break;
}
}
static void netlink_deliver_tap(struct sk_buff *skb)
{
rcu_read_lock();
if (unlikely(!list_empty(&netlink_tap_all)))
__netlink_deliver_tap(skb);
rcu_read_unlock();
}
static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
struct sk_buff *skb)
{
if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
netlink_deliver_tap(skb);
}
static void netlink_overrun(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
if (!test_and_set_bit(NETLINK_CONGESTED, &nlk_sk(sk)->state)) {
sk->sk_err = ENOBUFS;
sk->sk_error_report(sk);
}
}
atomic_inc(&sk->sk_drops);
}
static void netlink_rcv_wake(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (skb_queue_empty(&sk->sk_receive_queue))
clear_bit(NETLINK_CONGESTED, &nlk->state);
if (!test_bit(NETLINK_CONGESTED, &nlk->state))
wake_up_interruptible(&nlk->wait);
}
#ifdef CONFIG_NETLINK_MMAP
static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
{
return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
}
static bool netlink_rx_is_mmaped(struct sock *sk)
{
return nlk_sk(sk)->rx_ring.pg_vec != NULL;
}
static bool netlink_tx_is_mmaped(struct sock *sk)
{
return nlk_sk(sk)->tx_ring.pg_vec != NULL;
}
static __pure struct page *pgvec_to_page(const void *addr)
{
if (is_vmalloc_addr(addr))
return vmalloc_to_page(addr);
else
return virt_to_page(addr);
}
static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len)
{
unsigned int i;
for (i = 0; i < len; i++) {
if (pg_vec[i] != NULL) {
if (is_vmalloc_addr(pg_vec[i]))
vfree(pg_vec[i]);
else
free_pages((unsigned long)pg_vec[i], order);
}
}
kfree(pg_vec);
}
static void *alloc_one_pg_vec_page(unsigned long order)
{
void *buffer;
gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO |
__GFP_NOWARN | __GFP_NORETRY;
buffer = (void *)__get_free_pages(gfp_flags, order);
if (buffer != NULL)
return buffer;
buffer = vzalloc((1 << order) * PAGE_SIZE);
if (buffer != NULL)
return buffer;
gfp_flags &= ~__GFP_NORETRY;
return (void *)__get_free_pages(gfp_flags, order);
}
static void **alloc_pg_vec(struct netlink_sock *nlk,
struct nl_mmap_req *req, unsigned int order)
{
unsigned int block_nr = req->nm_block_nr;
unsigned int i;
void **pg_vec;
pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL);
if (pg_vec == NULL)
return NULL;
for (i = 0; i < block_nr; i++) {
pg_vec[i] = alloc_one_pg_vec_page(order);
if (pg_vec[i] == NULL)
goto err1;
}
return pg_vec;
err1:
free_pg_vec(pg_vec, order, block_nr);
return NULL;
}
static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req,
bool closing, bool tx_ring)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring;
struct sk_buff_head *queue;
void **pg_vec = NULL;
unsigned int order = 0;
int err;
ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring;
queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
if (!closing) {
if (atomic_read(&nlk->mapped))
return -EBUSY;
if (atomic_read(&ring->pending))
return -EBUSY;
}
if (req->nm_block_nr) {
if (ring->pg_vec != NULL)
return -EBUSY;
if ((int)req->nm_block_size <= 0)
return -EINVAL;
if (!IS_ALIGNED(req->nm_block_size, PAGE_SIZE))
return -EINVAL;
if (req->nm_frame_size < NL_MMAP_HDRLEN)
return -EINVAL;
if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT))
return -EINVAL;
ring->frames_per_block = req->nm_block_size /
req->nm_frame_size;
if (ring->frames_per_block == 0)
return -EINVAL;
if (ring->frames_per_block * req->nm_block_nr !=
req->nm_frame_nr)
return -EINVAL;
order = get_order(req->nm_block_size);
pg_vec = alloc_pg_vec(nlk, req, order);
if (pg_vec == NULL)
return -ENOMEM;
} else {
if (req->nm_frame_nr)
return -EINVAL;
}
err = -EBUSY;
mutex_lock(&nlk->pg_vec_lock);
if (closing || atomic_read(&nlk->mapped) == 0) {
err = 0;
spin_lock_bh(&queue->lock);
ring->frame_max = req->nm_frame_nr - 1;
ring->head = 0;
ring->frame_size = req->nm_frame_size;
ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE;
swap(ring->pg_vec_len, req->nm_block_nr);
swap(ring->pg_vec_order, order);
swap(ring->pg_vec, pg_vec);
__skb_queue_purge(queue);
spin_unlock_bh(&queue->lock);
WARN_ON(atomic_read(&nlk->mapped));
}
mutex_unlock(&nlk->pg_vec_lock);
if (pg_vec)
free_pg_vec(pg_vec, order, req->nm_block_nr);
return err;
}
static void netlink_mm_open(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct socket *sock = file->private_data;
struct sock *sk = sock->sk;
if (sk)
atomic_inc(&nlk_sk(sk)->mapped);
}
static void netlink_mm_close(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct socket *sock = file->private_data;
struct sock *sk = sock->sk;
if (sk)
atomic_dec(&nlk_sk(sk)->mapped);
}
static const struct vm_operations_struct netlink_mmap_ops = {
.open = netlink_mm_open,
.close = netlink_mm_close,
};
static int netlink_mmap(struct file *file, struct socket *sock,
struct vm_area_struct *vma)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring;
unsigned long start, size, expected;
unsigned int i;
int err = -EINVAL;
if (vma->vm_pgoff)
return -EINVAL;
mutex_lock(&nlk->pg_vec_lock);
expected = 0;
for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
if (ring->pg_vec == NULL)
continue;
expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE;
}
if (expected == 0)
goto out;
size = vma->vm_end - vma->vm_start;
if (size != expected)
goto out;
start = vma->vm_start;
for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
if (ring->pg_vec == NULL)
continue;
for (i = 0; i < ring->pg_vec_len; i++) {
struct page *page;
void *kaddr = ring->pg_vec[i];
unsigned int pg_num;
for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) {
page = pgvec_to_page(kaddr);
err = vm_insert_page(vma, start, page);
if (err < 0)
goto out;
start += PAGE_SIZE;
kaddr += PAGE_SIZE;
}
}
}
atomic_inc(&nlk->mapped);
vma->vm_ops = &netlink_mmap_ops;
err = 0;
out:
mutex_unlock(&nlk->pg_vec_lock);
return err;
}
static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr)
{
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
struct page *p_start, *p_end;
/* First page is flushed through netlink_{get,set}_status */
p_start = pgvec_to_page(hdr + PAGE_SIZE);
p_end = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + hdr->nm_len - 1);
while (p_start <= p_end) {
flush_dcache_page(p_start);
p_start++;
}
#endif
}
static enum nl_mmap_status netlink_get_status(const struct nl_mmap_hdr *hdr)
{
smp_rmb();
flush_dcache_page(pgvec_to_page(hdr));
return hdr->nm_status;
}
static void netlink_set_status(struct nl_mmap_hdr *hdr,
enum nl_mmap_status status)
{
hdr->nm_status = status;
flush_dcache_page(pgvec_to_page(hdr));
smp_wmb();
}
static struct nl_mmap_hdr *
__netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos)
{
unsigned int pg_vec_pos, frame_off;
pg_vec_pos = pos / ring->frames_per_block;
frame_off = pos % ring->frames_per_block;
return ring->pg_vec[pg_vec_pos] + (frame_off * ring->frame_size);
}
static struct nl_mmap_hdr *
netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos,
enum nl_mmap_status status)
{
struct nl_mmap_hdr *hdr;
hdr = __netlink_lookup_frame(ring, pos);
if (netlink_get_status(hdr) != status)
return NULL;
return hdr;
}
static struct nl_mmap_hdr *
netlink_current_frame(const struct netlink_ring *ring,
enum nl_mmap_status status)
{
return netlink_lookup_frame(ring, ring->head, status);
}
static struct nl_mmap_hdr *
netlink_previous_frame(const struct netlink_ring *ring,
enum nl_mmap_status status)
{
unsigned int prev;
prev = ring->head ? ring->head - 1 : ring->frame_max;
return netlink_lookup_frame(ring, prev, status);
}
static void netlink_increment_head(struct netlink_ring *ring)
{
ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0;
}
static void netlink_forward_ring(struct netlink_ring *ring)
{
unsigned int head = ring->head, pos = head;
const struct nl_mmap_hdr *hdr;
do {
hdr = __netlink_lookup_frame(ring, pos);
if (hdr->nm_status == NL_MMAP_STATUS_UNUSED)
break;
if (hdr->nm_status != NL_MMAP_STATUS_SKIP)
break;
netlink_increment_head(ring);
} while (ring->head != head);
}
static bool netlink_dump_space(struct netlink_sock *nlk)
{
struct netlink_ring *ring = &nlk->rx_ring;
struct nl_mmap_hdr *hdr;
unsigned int n;
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
if (hdr == NULL)
return false;
n = ring->head + ring->frame_max / 2;
if (n > ring->frame_max)
n -= ring->frame_max;
hdr = __netlink_lookup_frame(ring, n);
return hdr->nm_status == NL_MMAP_STATUS_UNUSED;
}
static unsigned int netlink_poll(struct file *file, struct socket *sock,
poll_table *wait)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
unsigned int mask;
int err;
if (nlk->rx_ring.pg_vec != NULL) {
/* Memory mapped sockets don't call recvmsg(), so flow control
* for dumps is performed here. A dump is allowed to continue
* if at least half the ring is unused.
*/
while (nlk->cb_running && netlink_dump_space(nlk)) {
err = netlink_dump(sk);
if (err < 0) {
sk->sk_err = -err;
sk->sk_error_report(sk);
break;
}
}
netlink_rcv_wake(sk);
}
mask = datagram_poll(file, sock, wait);
spin_lock_bh(&sk->sk_receive_queue.lock);
if (nlk->rx_ring.pg_vec) {
netlink_forward_ring(&nlk->rx_ring);
if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED))
mask |= POLLIN | POLLRDNORM;
}
spin_unlock_bh(&sk->sk_receive_queue.lock);
spin_lock_bh(&sk->sk_write_queue.lock);
if (nlk->tx_ring.pg_vec) {
if (netlink_current_frame(&nlk->tx_ring, NL_MMAP_STATUS_UNUSED))
mask |= POLLOUT | POLLWRNORM;
}
spin_unlock_bh(&sk->sk_write_queue.lock);
return mask;
}
static struct nl_mmap_hdr *netlink_mmap_hdr(struct sk_buff *skb)
{
return (struct nl_mmap_hdr *)(skb->head - NL_MMAP_HDRLEN);
}
static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
struct netlink_ring *ring,
struct nl_mmap_hdr *hdr)
{
unsigned int size;
void *data;
size = ring->frame_size - NL_MMAP_HDRLEN;
data = (void *)hdr + NL_MMAP_HDRLEN;
skb->head = data;
skb->data = data;
skb_reset_tail_pointer(skb);
skb->end = skb->tail + size;
skb->len = 0;
skb->destructor = netlink_skb_destructor;
NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
NETLINK_CB(skb).sk = sk;
}
static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
u32 dst_portid, u32 dst_group,
struct sock_iocb *siocb)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring;
struct nl_mmap_hdr *hdr;
struct sk_buff *skb;
unsigned int maxlen;
bool excl = true;
int err = 0, len = 0;
/* Netlink messages are validated by the receiver before processing.
* In order to avoid userspace changing the contents of the message
* after validation, the socket and the ring may only be used by a
* single process, otherwise we fall back to copying.
*/
if (atomic_long_read(&sk->sk_socket->file->f_count) > 2 ||
atomic_read(&nlk->mapped) > 1)
excl = false;
mutex_lock(&nlk->pg_vec_lock);
ring = &nlk->tx_ring;
maxlen = ring->frame_size - NL_MMAP_HDRLEN;
do {
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
if (hdr == NULL) {
if (!(msg->msg_flags & MSG_DONTWAIT) &&
atomic_read(&nlk->tx_ring.pending))
schedule();
continue;
}
if (hdr->nm_len > maxlen) {
err = -EINVAL;
goto out;
}
netlink_frame_flush_dcache(hdr);
if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
skb = alloc_skb_head(GFP_KERNEL);
if (skb == NULL) {
err = -ENOBUFS;
goto out;
}
sock_hold(sk);
netlink_ring_setup_skb(skb, sk, ring, hdr);
NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
__skb_put(skb, hdr->nm_len);
netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
atomic_inc(&ring->pending);
} else {
skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
if (skb == NULL) {
err = -ENOBUFS;
goto out;
}
__skb_put(skb, hdr->nm_len);
memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
}
netlink_increment_head(ring);
NETLINK_CB(skb).portid = nlk->portid;
NETLINK_CB(skb).dst_group = dst_group;
NETLINK_CB(skb).creds = siocb->scm->creds;
err = security_netlink_send(sk, skb);
if (err) {
kfree_skb(skb);
goto out;
}
if (unlikely(dst_group)) {
atomic_inc(&skb->users);
netlink_broadcast(sk, skb, dst_portid, dst_group,
GFP_KERNEL);
}
err = netlink_unicast(sk, skb, dst_portid,
msg->msg_flags & MSG_DONTWAIT);
if (err < 0)
goto out;
len += err;
} while (hdr != NULL ||
(!(msg->msg_flags & MSG_DONTWAIT) &&
atomic_read(&nlk->tx_ring.pending)));
if (len > 0)
err = len;
out:
mutex_unlock(&nlk->pg_vec_lock);
return err;
}
static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb)
{
struct nl_mmap_hdr *hdr;
hdr = netlink_mmap_hdr(skb);
hdr->nm_len = skb->len;
hdr->nm_group = NETLINK_CB(skb).dst_group;
hdr->nm_pid = NETLINK_CB(skb).creds.pid;
hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
netlink_frame_flush_dcache(hdr);
netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED;
kfree_skb(skb);
}
static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring = &nlk->rx_ring;
struct nl_mmap_hdr *hdr;
spin_lock_bh(&sk->sk_receive_queue.lock);
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
if (hdr == NULL) {
spin_unlock_bh(&sk->sk_receive_queue.lock);
kfree_skb(skb);
netlink_overrun(sk);
return;
}
netlink_increment_head(ring);
__skb_queue_tail(&sk->sk_receive_queue, skb);
spin_unlock_bh(&sk->sk_receive_queue.lock);
hdr->nm_len = skb->len;
hdr->nm_group = NETLINK_CB(skb).dst_group;
hdr->nm_pid = NETLINK_CB(skb).creds.pid;
hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
netlink_set_status(hdr, NL_MMAP_STATUS_COPY);
}
#else /* CONFIG_NETLINK_MMAP */
#define netlink_skb_is_mmaped(skb) false
#define netlink_rx_is_mmaped(sk) false
#define netlink_tx_is_mmaped(sk) false
#define netlink_mmap sock_no_mmap
#define netlink_poll datagram_poll
#define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
#endif /* CONFIG_NETLINK_MMAP */
static void netlink_skb_destructor(struct sk_buff *skb)
{
#ifdef CONFIG_NETLINK_MMAP
struct nl_mmap_hdr *hdr;
struct netlink_ring *ring;
struct sock *sk;
/* If a packet from the kernel to userspace was freed because of an
* error without being delivered to userspace, the kernel must reset
* the status. In the direction userspace to kernel, the status is
* always reset here after the packet was processed and freed.
*/
if (netlink_skb_is_mmaped(skb)) {
hdr = netlink_mmap_hdr(skb);
sk = NETLINK_CB(skb).sk;
if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
ring = &nlk_sk(sk)->tx_ring;
} else {
if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
hdr->nm_len = 0;
netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
}
ring = &nlk_sk(sk)->rx_ring;
}
WARN_ON(atomic_read(&ring->pending) == 0);
atomic_dec(&ring->pending);
sock_put(sk);
skb->head = NULL;
}
#endif
if (is_vmalloc_addr(skb->head)) {
if (!skb->cloned ||
!atomic_dec_return(&(skb_shinfo(skb)->dataref)))
vfree(skb->head);
skb->head = NULL;
}
if (skb->sk != NULL)
sock_rfree(skb);
}
static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
{
WARN_ON(skb->sk != NULL);
skb->sk = sk;
skb->destructor = netlink_skb_destructor;
atomic_add(skb->truesize, &sk->sk_rmem_alloc);
sk_mem_charge(sk, skb->truesize);
}
static void netlink_sock_destruct(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (nlk->cb_running) {
if (nlk->cb.done)
nlk->cb.done(&nlk->cb);
module_put(nlk->cb.module);
kfree_skb(nlk->cb.skb);
}
skb_queue_purge(&sk->sk_receive_queue);
#ifdef CONFIG_NETLINK_MMAP
if (1) {
struct nl_mmap_req req;
memset(&req, 0, sizeof(req));
if (nlk->rx_ring.pg_vec)
netlink_set_ring(sk, &req, true, false);
memset(&req, 0, sizeof(req));
if (nlk->tx_ring.pg_vec)
netlink_set_ring(sk, &req, true, true);
}
#endif /* CONFIG_NETLINK_MMAP */
if (!sock_flag(sk, SOCK_DEAD)) {
printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
return;
}
WARN_ON(atomic_read(&sk->sk_rmem_alloc));
WARN_ON(atomic_read(&sk->sk_wmem_alloc));
WARN_ON(nlk_sk(sk)->groups);
}
/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
* SMP. Look, when several writers sleep and reader wakes them up, all but one
* immediately hit write lock and grab all the cpus. Exclusive sleep solves
* this, _but_ remember, it adds useless work on UP machines.
*/
void netlink_table_grab(void)
__acquires(nl_table_lock)
{
might_sleep();
write_lock_irq(&nl_table_lock);
if (atomic_read(&nl_table_users)) {
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&nl_table_wait, &wait);
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (atomic_read(&nl_table_users) == 0)
break;
write_unlock_irq(&nl_table_lock);
schedule();
write_lock_irq(&nl_table_lock);
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(&nl_table_wait, &wait);
}
}
void netlink_table_ungrab(void)
__releases(nl_table_lock)
{
write_unlock_irq(&nl_table_lock);
wake_up(&nl_table_wait);
}
static inline void
netlink_lock_table(void)
{
/* read_lock() synchronizes us to netlink_table_grab */
read_lock(&nl_table_lock);
atomic_inc(&nl_table_users);
read_unlock(&nl_table_lock);
}
static inline void
netlink_unlock_table(void)
{
if (atomic_dec_and_test(&nl_table_users))
wake_up(&nl_table_wait);
}
static bool netlink_compare(struct net *net, struct sock *sk)
{
return net_eq(sock_net(sk), net);
}
static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
{
struct netlink_table *table = &nl_table[protocol];
struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
struct sock *sk;
read_lock(&nl_table_lock);
head = nl_portid_hashfn(hash, portid);
sk_for_each(sk, head) {
if (table->compare(net, sk) &&
(nlk_sk(sk)->portid == portid)) {
sock_hold(sk);
goto found;
}
}
sk = NULL;
found:
read_unlock(&nl_table_lock);
return sk;
}
static struct hlist_head *nl_portid_hash_zalloc(size_t size)
{
if (size <= PAGE_SIZE)
return kzalloc(size, GFP_ATOMIC);
else
return (struct hlist_head *)
__get_free_pages(GFP_ATOMIC | __GFP_ZERO,
get_order(size));
}
static void nl_portid_hash_free(struct hlist_head *table, size_t size)
{
if (size <= PAGE_SIZE)
kfree(table);
else
free_pages((unsigned long)table, get_order(size));
}
static int nl_portid_hash_rehash(struct nl_portid_hash *hash, int grow)
{
unsigned int omask, mask, shift;
size_t osize, size;
struct hlist_head *otable, *table;
int i;
omask = mask = hash->mask;
osize = size = (mask + 1) * sizeof(*table);
shift = hash->shift;
if (grow) {
if (++shift > hash->max_shift)
return 0;
mask = mask * 2 + 1;
size *= 2;
}
table = nl_portid_hash_zalloc(size);
if (!table)
return 0;
otable = hash->table;
hash->table = table;
hash->mask = mask;
hash->shift = shift;
get_random_bytes(&hash->rnd, sizeof(hash->rnd));
for (i = 0; i <= omask; i++) {
struct sock *sk;
struct hlist_node *tmp;
sk_for_each_safe(sk, tmp, &otable[i])
__sk_add_node(sk, nl_portid_hashfn(hash, nlk_sk(sk)->portid));
}
nl_portid_hash_free(otable, osize);
hash->rehash_time = jiffies + 10 * 60 * HZ;
return 1;
}
static inline int nl_portid_hash_dilute(struct nl_portid_hash *hash, int len)
{
int avg = hash->entries >> hash->shift;
if (unlikely(avg > 1) && nl_portid_hash_rehash(hash, 1))
return 1;
if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
nl_portid_hash_rehash(hash, 0);
return 1;
}
return 0;
}
static const struct proto_ops netlink_ops;
static void
netlink_update_listeners(struct sock *sk)
{
struct netlink_table *tbl = &nl_table[sk->sk_protocol];
unsigned long mask;
unsigned int i;
struct listeners *listeners;
listeners = nl_deref_protected(tbl->listeners);
if (!listeners)
return;
for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
mask = 0;
sk_for_each_bound(sk, &tbl->mc_list) {
if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
mask |= nlk_sk(sk)->groups[i];
}
listeners->masks[i] = mask;
}
/* this function is only called with the netlink table "grabbed", which
* makes sure updates are visible before bind or setsockopt return. */
}
static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
{
struct netlink_table *table = &nl_table[sk->sk_protocol];
struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
int err = -EADDRINUSE;
struct sock *osk;
int len;
netlink_table_grab();
head = nl_portid_hashfn(hash, portid);
len = 0;
sk_for_each(osk, head) {
if (table->compare(net, osk) &&
(nlk_sk(osk)->portid == portid))
break;
len++;
}
if (osk)
goto err;
err = -EBUSY;
if (nlk_sk(sk)->portid)
goto err;
err = -ENOMEM;
if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
goto err;
if (len && nl_portid_hash_dilute(hash, len))
head = nl_portid_hashfn(hash, portid);
hash->entries++;
nlk_sk(sk)->portid = portid;
sk_add_node(sk, head);
err = 0;
err:
netlink_table_ungrab();
return err;
}
static void netlink_remove(struct sock *sk)
{
netlink_table_grab();
if (sk_del_node_init(sk))
nl_table[sk->sk_protocol].hash.entries--;
if (nlk_sk(sk)->subscriptions)
__sk_del_bind_node(sk);
netlink_table_ungrab();
}
static struct proto netlink_proto = {
.name = "NETLINK",
.owner = THIS_MODULE,
.obj_size = sizeof(struct netlink_sock),
};
static int __netlink_create(struct net *net, struct socket *sock,
struct mutex *cb_mutex, int protocol)
{
struct sock *sk;
struct netlink_sock *nlk;
sock->ops = &netlink_ops;
sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
if (!sk)
return -ENOMEM;
sock_init_data(sock, sk);
nlk = nlk_sk(sk);
if (cb_mutex) {
nlk->cb_mutex = cb_mutex;
} else {
nlk->cb_mutex = &nlk->cb_def_mutex;
mutex_init(nlk->cb_mutex);
}
init_waitqueue_head(&nlk->wait);
#ifdef CONFIG_NETLINK_MMAP
mutex_init(&nlk->pg_vec_lock);
#endif
sk->sk_destruct = netlink_sock_destruct;
sk->sk_protocol = protocol;
return 0;
}
static int netlink_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct module *module = NULL;
struct mutex *cb_mutex;
struct netlink_sock *nlk;
int (*bind)(int group);
void (*unbind)(int group);
int err = 0;
sock->state = SS_UNCONNECTED;
if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
return -ESOCKTNOSUPPORT;
if (protocol < 0 || protocol >= MAX_LINKS)
return -EPROTONOSUPPORT;
netlink_lock_table();
#ifdef CONFIG_MODULES
if (!nl_table[protocol].registered) {
netlink_unlock_table();
request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
netlink_lock_table();
}
#endif
if (nl_table[protocol].registered &&
try_module_get(nl_table[protocol].module))
module = nl_table[protocol].module;
else
err = -EPROTONOSUPPORT;
cb_mutex = nl_table[protocol].cb_mutex;
bind = nl_table[protocol].bind;
unbind = nl_table[protocol].unbind;
netlink_unlock_table();
if (err < 0)
goto out;
err = __netlink_create(net, sock, cb_mutex, protocol);
if (err < 0)
goto out_module;
local_bh_disable();
sock_prot_inuse_add(net, &netlink_proto, 1);
local_bh_enable();
nlk = nlk_sk(sock->sk);
nlk->module = module;
nlk->netlink_bind = bind;
nlk->netlink_unbind = unbind;
out:
return err;
out_module:
module_put(module);
goto out;
}
static int netlink_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk;
if (!sk)
return 0;
netlink_remove(sk);
sock_orphan(sk);
nlk = nlk_sk(sk);
/*
* OK. Socket is unlinked, any packets that arrive now
* will be purged.
*/
sock->sk = NULL;
wake_up_interruptible_all(&nlk->wait);
skb_queue_purge(&sk->sk_write_queue);
if (nlk->portid) {
struct netlink_notify n = {
.net = sock_net(sk),
.protocol = sk->sk_protocol,
.portid = nlk->portid,
};
atomic_notifier_call_chain(&netlink_chain,
NETLINK_URELEASE, &n);
}
module_put(nlk->module);
netlink_table_grab();
if (netlink_is_kernel(sk)) {
BUG_ON(nl_table[sk->sk_protocol].registered == 0);
if (--nl_table[sk->sk_protocol].registered == 0) {
struct listeners *old;
old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
kfree_rcu(old, rcu);
nl_table[sk->sk_protocol].module = NULL;
nl_table[sk->sk_protocol].bind = NULL;
nl_table[sk->sk_protocol].unbind = NULL;
nl_table[sk->sk_protocol].flags = 0;
nl_table[sk->sk_protocol].registered = 0;
}
} else if (nlk->subscriptions) {
netlink_update_listeners(sk);
}
netlink_table_ungrab();
kfree(nlk->groups);
nlk->groups = NULL;
local_bh_disable();
sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
local_bh_enable();
sock_put(sk);
return 0;
}
static int netlink_autobind(struct socket *sock)
{
struct sock *sk = sock->sk;
struct net *net = sock_net(sk);
struct netlink_table *table = &nl_table[sk->sk_protocol];
struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
struct sock *osk;
s32 portid = task_tgid_vnr(current);
int err;
static s32 rover = -4097;
retry:
cond_resched();
netlink_table_grab();
head = nl_portid_hashfn(hash, portid);
sk_for_each(osk, head) {
if (!table->compare(net, osk))
continue;
if (nlk_sk(osk)->portid == portid) {
/* Bind collision, search negative portid values. */
portid = rover--;
if (rover > -4097)
rover = -4097;
netlink_table_ungrab();
goto retry;
}
}
netlink_table_ungrab();
err = netlink_insert(sk, net, portid);
if (err == -EADDRINUSE)
goto retry;
/* If 2 threads race to autobind, that is fine. */
if (err == -EBUSY)
err = 0;
return err;
}
/**
* __netlink_ns_capable - General netlink message capability test
* @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
* @user_ns: The user namespace of the capability to use
* @cap: The capability to use
*
* Test to see if the opener of the socket we received the message
* from had when the netlink socket was created and the sender of the
* message has has the capability @cap in the user namespace @user_ns.
*/
bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
struct user_namespace *user_ns, int cap)
{
return ((nsp->flags & NETLINK_SKB_DST) ||
file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
ns_capable(user_ns, cap);
}
EXPORT_SYMBOL(__netlink_ns_capable);
/**
* netlink_ns_capable - General netlink message capability test
* @skb: socket buffer holding a netlink command from userspace
* @user_ns: The user namespace of the capability to use
* @cap: The capability to use
*
* Test to see if the opener of the socket we received the message
* from had when the netlink socket was created and the sender of the
* message has has the capability @cap in the user namespace @user_ns.
*/
bool netlink_ns_capable(const struct sk_buff *skb,
struct user_namespace *user_ns, int cap)
{
return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
}
EXPORT_SYMBOL(netlink_ns_capable);
/**
* netlink_capable - Netlink global message capability test
* @skb: socket buffer holding a netlink command from userspace
* @cap: The capability to use
*
* Test to see if the opener of the socket we received the message
* from had when the netlink socket was created and the sender of the
* message has has the capability @cap in all user namespaces.
*/
bool netlink_capable(const struct sk_buff *skb, int cap)
{
return netlink_ns_capable(skb, &init_user_ns, cap);
}
EXPORT_SYMBOL(netlink_capable);
/**
* netlink_net_capable - Netlink network namespace message capability test
* @skb: socket buffer holding a netlink command from userspace
* @cap: The capability to use
*
* Test to see if the opener of the socket we received the message
* from had when the netlink socket was created and the sender of the
* message has has the capability @cap over the network namespace of
* the socket we received the message from.
*/
bool netlink_net_capable(const struct sk_buff *skb, int cap)
{
return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
}
EXPORT_SYMBOL(netlink_net_capable);
static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
{
return (nl_table[sock->sk->sk_protocol].flags & flag) ||
ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
}
static void
netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (nlk->subscriptions && !subscriptions)
__sk_del_bind_node(sk);
else if (!nlk->subscriptions && subscriptions)
sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
nlk->subscriptions = subscriptions;
}
static int netlink_realloc_groups(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
unsigned int groups;
unsigned long *new_groups;
int err = 0;
netlink_table_grab();
groups = nl_table[sk->sk_protocol].groups;
if (!nl_table[sk->sk_protocol].registered) {
err = -ENOENT;
goto out_unlock;
}
if (nlk->ngroups >= groups)
goto out_unlock;
new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
if (new_groups == NULL) {
err = -ENOMEM;
goto out_unlock;
}
memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
nlk->groups = new_groups;
nlk->ngroups = groups;
out_unlock:
netlink_table_ungrab();
return err;
}
static void netlink_unbind(int group, long unsigned int groups,
struct netlink_sock *nlk)
{
int undo;
if (!nlk->netlink_unbind)
return;
for (undo = 0; undo < group; undo++)
if (test_bit(group, &groups))
nlk->netlink_unbind(undo);
}
static int netlink_bind(struct socket *sock, struct sockaddr *addr,
int addr_len)
{
struct sock *sk = sock->sk;
struct net *net = sock_net(sk);
struct netlink_sock *nlk = nlk_sk(sk);
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
int err;
long unsigned int groups = nladdr->nl_groups;
if (addr_len < sizeof(struct sockaddr_nl))
return -EINVAL;
if (nladdr->nl_family != AF_NETLINK)
return -EINVAL;
/* Only superuser is allowed to listen multicasts */
if (groups) {
if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
return -EPERM;
err = netlink_realloc_groups(sk);
if (err)
return err;
}
if (nlk->portid)
if (nladdr->nl_pid != nlk->portid)
return -EINVAL;
if (nlk->netlink_bind && groups) {
int group;
for (group = 0; group < nlk->ngroups; group++) {
if (!test_bit(group, &groups))
continue;
err = nlk->netlink_bind(group);
if (!err)
continue;
netlink_unbind(group, groups, nlk);
return err;
}
}
if (!nlk->portid) {
err = nladdr->nl_pid ?
netlink_insert(sk, net, nladdr->nl_pid) :
netlink_autobind(sock);
if (err) {
netlink_unbind(nlk->ngroups - 1, groups, nlk);
return err;
}
}
if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
return 0;
netlink_table_grab();
netlink_update_subscriptions(sk, nlk->subscriptions +
hweight32(groups) -
hweight32(nlk->groups[0]));
nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
netlink_update_listeners(sk);
netlink_table_ungrab();
return 0;
}
static int netlink_connect(struct socket *sock, struct sockaddr *addr,
int alen, int flags)
{
int err = 0;
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
if (alen < sizeof(addr->sa_family))
return -EINVAL;
if (addr->sa_family == AF_UNSPEC) {
sk->sk_state = NETLINK_UNCONNECTED;
nlk->dst_portid = 0;
nlk->dst_group = 0;
return 0;
}
if (addr->sa_family != AF_NETLINK)
return -EINVAL;
if ((nladdr->nl_groups || nladdr->nl_pid) &&
!netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
return -EPERM;
if (!nlk->portid)
err = netlink_autobind(sock);
if (err == 0) {
sk->sk_state = NETLINK_CONNECTED;
nlk->dst_portid = nladdr->nl_pid;
nlk->dst_group = ffs(nladdr->nl_groups);
}
return err;
}
static int netlink_getname(struct socket *sock, struct sockaddr *addr,
int *addr_len, int peer)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
nladdr->nl_family = AF_NETLINK;
nladdr->nl_pad = 0;
*addr_len = sizeof(*nladdr);
if (peer) {
nladdr->nl_pid = nlk->dst_portid;
nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
} else {
nladdr->nl_pid = nlk->portid;
nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
}
return 0;
}
static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
{
struct sock *sock;
struct netlink_sock *nlk;
sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
if (!sock)
return ERR_PTR(-ECONNREFUSED);
/* Don't bother queuing skb if kernel socket has no input function */
nlk = nlk_sk(sock);
if (sock->sk_state == NETLINK_CONNECTED &&
nlk->dst_portid != nlk_sk(ssk)->portid) {
sock_put(sock);
return ERR_PTR(-ECONNREFUSED);
}
return sock;
}
struct sock *netlink_getsockbyfilp(struct file *filp)
{
struct inode *inode = file_inode(filp);
struct sock *sock;
if (!S_ISSOCK(inode->i_mode))
return ERR_PTR(-ENOTSOCK);
sock = SOCKET_I(inode)->sk;
if (sock->sk_family != AF_NETLINK)
return ERR_PTR(-EINVAL);
sock_hold(sock);
return sock;
}
static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
int broadcast)
{
struct sk_buff *skb;
void *data;
if (size <= NLMSG_GOODSIZE || broadcast)
return alloc_skb(size, GFP_KERNEL);
size = SKB_DATA_ALIGN(size) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
data = vmalloc(size);
if (data == NULL)
return NULL;
skb = build_skb(data, size);
if (skb == NULL)
vfree(data);
else {
skb->head_frag = 0;
skb->destructor = netlink_skb_destructor;
}
return skb;
}
/*
* Attach a skb to a netlink socket.
* The caller must hold a reference to the destination socket. On error, the
* reference is dropped. The skb is not send to the destination, just all
* all error checks are performed and memory in the queue is reserved.
* Return values:
* < 0: error. skb freed, reference to sock dropped.
* 0: continue
* 1: repeat lookup - reference dropped while waiting for socket memory.
*/
int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
long *timeo, struct sock *ssk)
{
struct netlink_sock *nlk;
nlk = nlk_sk(sk);
if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
test_bit(NETLINK_CONGESTED, &nlk->state)) &&
!netlink_skb_is_mmaped(skb)) {
DECLARE_WAITQUEUE(wait, current);
if (!*timeo) {
if (!ssk || netlink_is_kernel(ssk))
netlink_overrun(sk);
sock_put(sk);
kfree_skb(skb);
return -EAGAIN;
}
__set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&nlk->wait, &wait);
if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
test_bit(NETLINK_CONGESTED, &nlk->state)) &&
!sock_flag(sk, SOCK_DEAD))
*timeo = schedule_timeout(*timeo);
__set_current_state(TASK_RUNNING);
remove_wait_queue(&nlk->wait, &wait);
sock_put(sk);
if (signal_pending(current)) {
kfree_skb(skb);
return sock_intr_errno(*timeo);
}
return 1;
}
netlink_skb_set_owner_r(skb, sk);
return 0;
}
static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
{
int len = skb->len;
netlink_deliver_tap(skb);
#ifdef CONFIG_NETLINK_MMAP
if (netlink_skb_is_mmaped(skb))
netlink_queue_mmaped_skb(sk, skb);
else if (netlink_rx_is_mmaped(sk))
netlink_ring_set_copied(sk, skb);
else
#endif /* CONFIG_NETLINK_MMAP */
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_data_ready(sk);
return len;
}
int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
{
int len = __netlink_sendskb(sk, skb);
sock_put(sk);
return len;
}
void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
{
kfree_skb(skb);
sock_put(sk);
}
static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
{
int delta;
WARN_ON(skb->sk != NULL);
if (netlink_skb_is_mmaped(skb))
return skb;
delta = skb->end - skb->tail;
if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
return skb;
if (skb_shared(skb)) {
struct sk_buff *nskb = skb_clone(skb, allocation);
if (!nskb)
return skb;
consume_skb(skb);
skb = nskb;
}
if (!pskb_expand_head(skb, 0, -delta, allocation))
skb->truesize -= delta;
return skb;
}
static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
struct sock *ssk)
{
int ret;
struct netlink_sock *nlk = nlk_sk(sk);
ret = -ECONNREFUSED;
if (nlk->netlink_rcv != NULL) {
ret = skb->len;
netlink_skb_set_owner_r(skb, sk);
NETLINK_CB(skb).sk = ssk;
netlink_deliver_tap_kernel(sk, ssk, skb);
nlk->netlink_rcv(skb);
consume_skb(skb);
} else {
kfree_skb(skb);
}
sock_put(sk);
return ret;
}
int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
u32 portid, int nonblock)
{
struct sock *sk;
int err;
long timeo;
skb = netlink_trim(skb, gfp_any());
timeo = sock_sndtimeo(ssk, nonblock);
retry:
sk = netlink_getsockbyportid(ssk, portid);
if (IS_ERR(sk)) {
kfree_skb(skb);
return PTR_ERR(sk);
}
if (netlink_is_kernel(sk))
return netlink_unicast_kernel(sk, skb, ssk);
if (sk_filter(sk, skb)) {
err = skb->len;
kfree_skb(skb);
sock_put(sk);
return err;
}
err = netlink_attachskb(sk, skb, &timeo, ssk);
if (err == 1)
goto retry;
if (err)
return err;
return netlink_sendskb(sk, skb);
}
EXPORT_SYMBOL(netlink_unicast);
struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
u32 dst_portid, gfp_t gfp_mask)
{
#ifdef CONFIG_NETLINK_MMAP
struct sock *sk = NULL;
struct sk_buff *skb;
struct netlink_ring *ring;
struct nl_mmap_hdr *hdr;
unsigned int maxlen;
sk = netlink_getsockbyportid(ssk, dst_portid);
if (IS_ERR(sk))
goto out;
ring = &nlk_sk(sk)->rx_ring;
/* fast-path without atomic ops for common case: non-mmaped receiver */
if (ring->pg_vec == NULL)
goto out_put;
if (ring->frame_size - NL_MMAP_HDRLEN < size)
goto out_put;
skb = alloc_skb_head(gfp_mask);
if (skb == NULL)
goto err1;
spin_lock_bh(&sk->sk_receive_queue.lock);
/* check again under lock */
if (ring->pg_vec == NULL)
goto out_free;
/* check again under lock */
maxlen = ring->frame_size - NL_MMAP_HDRLEN;
if (maxlen < size)
goto out_free;
netlink_forward_ring(ring);
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
if (hdr == NULL)
goto err2;
netlink_ring_setup_skb(skb, sk, ring, hdr);
netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
atomic_inc(&ring->pending);
netlink_increment_head(ring);
spin_unlock_bh(&sk->sk_receive_queue.lock);
return skb;
err2:
kfree_skb(skb);
spin_unlock_bh(&sk->sk_receive_queue.lock);
netlink_overrun(sk);
err1:
sock_put(sk);
return NULL;
out_free:
kfree_skb(skb);
spin_unlock_bh(&sk->sk_receive_queue.lock);
out_put:
sock_put(sk);
out:
#endif
return alloc_skb(size, gfp_mask);
}
EXPORT_SYMBOL_GPL(netlink_alloc_skb);
int netlink_has_listeners(struct sock *sk, unsigned int group)
{
int res = 0;
struct listeners *listeners;
BUG_ON(!netlink_is_kernel(sk));
rcu_read_lock();
listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
res = test_bit(group - 1, listeners->masks);
rcu_read_unlock();
return res;
}
EXPORT_SYMBOL_GPL(netlink_has_listeners);
static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
!test_bit(NETLINK_CONGESTED, &nlk->state)) {
netlink_skb_set_owner_r(skb, sk);
__netlink_sendskb(sk, skb);
return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
}
return -1;
}
struct netlink_broadcast_data {
struct sock *exclude_sk;
struct net *net;
u32 portid;
u32 group;
int failure;
int delivery_failure;
int congested;
int delivered;
gfp_t allocation;
struct sk_buff *skb, *skb2;
int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
void *tx_data;
};
static int do_one_broadcast(struct sock *sk,
struct netlink_broadcast_data *p)
{
struct netlink_sock *nlk = nlk_sk(sk);
int val;
if (p->exclude_sk == sk)
goto out;
if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
!test_bit(p->group - 1, nlk->groups))
goto out;
if (!net_eq(sock_net(sk), p->net))
goto out;
if (p->failure) {
netlink_overrun(sk);
goto out;
}
sock_hold(sk);
if (p->skb2 == NULL) {
if (skb_shared(p->skb)) {
p->skb2 = skb_clone(p->skb, p->allocation);
} else {
p->skb2 = skb_get(p->skb);
/*
* skb ownership may have been set when
* delivered to a previous socket.
*/
skb_orphan(p->skb2);
}
}
if (p->skb2 == NULL) {
netlink_overrun(sk);
/* Clone failed. Notify ALL listeners. */
p->failure = 1;
if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
p->delivery_failure = 1;
} else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
kfree_skb(p->skb2);
p->skb2 = NULL;
} else if (sk_filter(sk, p->skb2)) {
kfree_skb(p->skb2);
p->skb2 = NULL;
} else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
netlink_overrun(sk);
if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
p->delivery_failure = 1;
} else {
p->congested |= val;
p->delivered = 1;
p->skb2 = NULL;
}
sock_put(sk);
out:
return 0;
}
int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
u32 group, gfp_t allocation,
int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
void *filter_data)
{
struct net *net = sock_net(ssk);
struct netlink_broadcast_data info;
struct sock *sk;
skb = netlink_trim(skb, allocation);
info.exclude_sk = ssk;
info.net = net;
info.portid = portid;
info.group = group;
info.failure = 0;
info.delivery_failure = 0;
info.congested = 0;
info.delivered = 0;
info.allocation = allocation;
info.skb = skb;
info.skb2 = NULL;
info.tx_filter = filter;
info.tx_data = filter_data;
/* While we sleep in clone, do not allow to change socket list */
netlink_lock_table();
sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
do_one_broadcast(sk, &info);
consume_skb(skb);
netlink_unlock_table();
if (info.delivery_failure) {
kfree_skb(info.skb2);
return -ENOBUFS;
}
consume_skb(info.skb2);
if (info.delivered) {
if (info.congested && (allocation & __GFP_WAIT))
yield();
return 0;
}
return -ESRCH;
}
EXPORT_SYMBOL(netlink_broadcast_filtered);
int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
u32 group, gfp_t allocation)
{
return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
NULL, NULL);
}
EXPORT_SYMBOL(netlink_broadcast);
struct netlink_set_err_data {
struct sock *exclude_sk;
u32 portid;
u32 group;
int code;
};
static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
{
struct netlink_sock *nlk = nlk_sk(sk);
int ret = 0;
if (sk == p->exclude_sk)
goto out;
if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
goto out;
if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
!test_bit(p->group - 1, nlk->groups))
goto out;
if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
ret = 1;
goto out;
}
sk->sk_err = p->code;
sk->sk_error_report(sk);
out:
return ret;
}
/**
* netlink_set_err - report error to broadcast listeners
* @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
* @portid: the PORTID of a process that we want to skip (if any)
* @group: the broadcast group that will notice the error
* @code: error code, must be negative (as usual in kernelspace)
*
* This function returns the number of broadcast listeners that have set the
* NETLINK_RECV_NO_ENOBUFS socket option.
*/
int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
{
struct netlink_set_err_data info;
struct sock *sk;
int ret = 0;
info.exclude_sk = ssk;
info.portid = portid;
info.group = group;
/* sk->sk_err wants a positive error value */
info.code = -code;
read_lock(&nl_table_lock);
sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
ret += do_one_set_err(sk, &info);
read_unlock(&nl_table_lock);
return ret;
}
EXPORT_SYMBOL(netlink_set_err);
/* must be called with netlink table grabbed */
static void netlink_update_socket_mc(struct netlink_sock *nlk,
unsigned int group,
int is_new)
{
int old, new = !!is_new, subscriptions;
old = test_bit(group - 1, nlk->groups);
subscriptions = nlk->subscriptions - old + new;
if (new)
__set_bit(group - 1, nlk->groups);
else
__clear_bit(group - 1, nlk->groups);
netlink_update_subscriptions(&nlk->sk, subscriptions);
netlink_update_listeners(&nlk->sk);
}
static int netlink_setsockopt(struct socket *sock, int level, int optname,
char __user *optval, unsigned int optlen)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
unsigned int val = 0;
int err;
if (level != SOL_NETLINK)
return -ENOPROTOOPT;
if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING &&
optlen >= sizeof(int) &&
get_user(val, (unsigned int __user *)optval))
return -EFAULT;
switch (optname) {
case NETLINK_PKTINFO:
if (val)
nlk->flags |= NETLINK_RECV_PKTINFO;
else
nlk->flags &= ~NETLINK_RECV_PKTINFO;
err = 0;
break;
case NETLINK_ADD_MEMBERSHIP:
case NETLINK_DROP_MEMBERSHIP: {
if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
return -EPERM;
err = netlink_realloc_groups(sk);
if (err)
return err;
if (!val || val - 1 >= nlk->ngroups)
return -EINVAL;
if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
err = nlk->netlink_bind(val);
if (err)
return err;
}
netlink_table_grab();
netlink_update_socket_mc(nlk, val,
optname == NETLINK_ADD_MEMBERSHIP);
netlink_table_ungrab();
if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
nlk->netlink_unbind(val);
err = 0;
break;
}
case NETLINK_BROADCAST_ERROR:
if (val)
nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
else
nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
err = 0;
break;
case NETLINK_NO_ENOBUFS:
if (val) {
nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
clear_bit(NETLINK_CONGESTED, &nlk->state);
wake_up_interruptible(&nlk->wait);
} else {
nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
}
err = 0;
break;
#ifdef CONFIG_NETLINK_MMAP
case NETLINK_RX_RING:
case NETLINK_TX_RING: {
struct nl_mmap_req req;
/* Rings might consume more memory than queue limits, require
* CAP_NET_ADMIN.
*/
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (optlen < sizeof(req))
return -EINVAL;
if (copy_from_user(&req, optval, sizeof(req)))
return -EFAULT;
err = netlink_set_ring(sk, &req, false,
optname == NETLINK_TX_RING);
break;
}
#endif /* CONFIG_NETLINK_MMAP */
default:
err = -ENOPROTOOPT;
}
return err;
}
static int netlink_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
int len, val, err;
if (level != SOL_NETLINK)
return -ENOPROTOOPT;
if (get_user(len, optlen))
return -EFAULT;
if (len < 0)
return -EINVAL;
switch (optname) {
case NETLINK_PKTINFO:
if (len < sizeof(int))
return -EINVAL;
len = sizeof(int);
val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
if (put_user(len, optlen) ||
put_user(val, optval))
return -EFAULT;
err = 0;
break;
case NETLINK_BROADCAST_ERROR:
if (len < sizeof(int))
return -EINVAL;
len = sizeof(int);
val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
if (put_user(len, optlen) ||
put_user(val, optval))
return -EFAULT;
err = 0;
break;
case NETLINK_NO_ENOBUFS:
if (len < sizeof(int))
return -EINVAL;
len = sizeof(int);
val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
if (put_user(len, optlen) ||
put_user(val, optval))
return -EFAULT;
err = 0;
break;
default:
err = -ENOPROTOOPT;
}
return err;
}
static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
{
struct nl_pktinfo info;
info.group = NETLINK_CB(skb).dst_group;
put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
}
static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
struct msghdr *msg, size_t len)
{
struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
u32 dst_portid;
u32 dst_group;
struct sk_buff *skb;
int err;
struct scm_cookie scm;
u32 netlink_skb_flags = 0;
if (msg->msg_flags&MSG_OOB)
return -EOPNOTSUPP;
if (NULL == siocb->scm)
siocb->scm = &scm;
err = scm_send(sock, msg, siocb->scm, true);
if (err < 0)
return err;
if (msg->msg_namelen) {
err = -EINVAL;
if (addr->nl_family != AF_NETLINK)
goto out;
dst_portid = addr->nl_pid;
dst_group = ffs(addr->nl_groups);
err = -EPERM;
if ((dst_group || dst_portid) &&
!netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
goto out;
netlink_skb_flags |= NETLINK_SKB_DST;
} else {
dst_portid = nlk->dst_portid;
dst_group = nlk->dst_group;
}
if (!nlk->portid) {
err = netlink_autobind(sock);
if (err)
goto out;
}
if (netlink_tx_is_mmaped(sk) &&
msg->msg_iov->iov_base == NULL) {
err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
siocb);
goto out;
}
err = -EMSGSIZE;
if (len > sk->sk_sndbuf - 32)
goto out;
err = -ENOBUFS;
skb = netlink_alloc_large_skb(len, dst_group);
if (skb == NULL)
goto out;
NETLINK_CB(skb).portid = nlk->portid;
NETLINK_CB(skb).dst_group = dst_group;
NETLINK_CB(skb).creds = siocb->scm->creds;
NETLINK_CB(skb).flags = netlink_skb_flags;
err = -EFAULT;
if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
kfree_skb(skb);
goto out;
}
err = security_netlink_send(sk, skb);
if (err) {
kfree_skb(skb);
goto out;
}
if (dst_group) {
atomic_inc(&skb->users);
netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
}
err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
out:
scm_destroy(siocb->scm);
return err;
}
static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
struct msghdr *msg, size_t len,
int flags)
{
struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
struct scm_cookie scm;
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
int noblock = flags&MSG_DONTWAIT;
size_t copied;
struct sk_buff *skb, *data_skb;
int err, ret;
if (flags&MSG_OOB)
return -EOPNOTSUPP;
copied = 0;
skb = skb_recv_datagram(sk, flags, noblock, &err);
if (skb == NULL)
goto out;
data_skb = skb;
#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
if (unlikely(skb_shinfo(skb)->frag_list)) {
/*
* If this skb has a frag_list, then here that means that we
* will have to use the frag_list skb's data for compat tasks
* and the regular skb's data for normal (non-compat) tasks.
*
* If we need to send the compat skb, assign it to the
* 'data_skb' variable so that it will be used below for data
* copying. We keep 'skb' for everything else, including
* freeing both later.
*/
if (flags & MSG_CMSG_COMPAT)
data_skb = skb_shinfo(skb)->frag_list;
}
#endif
/* Record the max length of recvmsg() calls for future allocations */
nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
16384);
copied = data_skb->len;
if (len < copied) {
msg->msg_flags |= MSG_TRUNC;
copied = len;
}
skb_reset_transport_header(data_skb);
err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
if (msg->msg_name) {
DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
addr->nl_family = AF_NETLINK;
addr->nl_pad = 0;
addr->nl_pid = NETLINK_CB(skb).portid;
addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
msg->msg_namelen = sizeof(*addr);
}
if (nlk->flags & NETLINK_RECV_PKTINFO)
netlink_cmsg_recv_pktinfo(msg, skb);
if (NULL == siocb->scm) {
memset(&scm, 0, sizeof(scm));
siocb->scm = &scm;
}
siocb->scm->creds = *NETLINK_CREDS(skb);
if (flags & MSG_TRUNC)
copied = data_skb->len;
skb_free_datagram(sk, skb);
if (nlk->cb_running &&
atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
ret = netlink_dump(sk);
if (ret) {
sk->sk_err = -ret;
sk->sk_error_report(sk);
}
}
scm_recv(sock, msg, siocb->scm, flags);
out:
netlink_rcv_wake(sk);
return err ? : copied;
}
static void netlink_data_ready(struct sock *sk)
{
BUG();
}
/*
* We export these functions to other modules. They provide a
* complete set of kernel non-blocking support for message
* queueing.
*/
struct sock *
__netlink_kernel_create(struct net *net, int unit, struct module *module,
struct netlink_kernel_cfg *cfg)
{
struct socket *sock;
struct sock *sk;
struct netlink_sock *nlk;
struct listeners *listeners = NULL;
struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
unsigned int groups;
BUG_ON(!nl_table);
if (unit < 0 || unit >= MAX_LINKS)
return NULL;
if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
return NULL;
/*
* We have to just have a reference on the net from sk, but don't
* get_net it. Besides, we cannot get and then put the net here.
* So we create one inside init_net and the move it to net.
*/
if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
goto out_sock_release_nosk;
sk = sock->sk;
sk_change_net(sk, net);
if (!cfg || cfg->groups < 32)
groups = 32;
else
groups = cfg->groups;
listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
if (!listeners)
goto out_sock_release;
sk->sk_data_ready = netlink_data_ready;
if (cfg && cfg->input)
nlk_sk(sk)->netlink_rcv = cfg->input;
if (netlink_insert(sk, net, 0))
goto out_sock_release;
nlk = nlk_sk(sk);
nlk->flags |= NETLINK_KERNEL_SOCKET;
netlink_table_grab();
if (!nl_table[unit].registered) {
nl_table[unit].groups = groups;
rcu_assign_pointer(nl_table[unit].listeners, listeners);
nl_table[unit].cb_mutex = cb_mutex;
nl_table[unit].module = module;
if (cfg) {
nl_table[unit].bind = cfg->bind;
nl_table[unit].flags = cfg->flags;
if (cfg->compare)
nl_table[unit].compare = cfg->compare;
}
nl_table[unit].registered = 1;
} else {
kfree(listeners);
nl_table[unit].registered++;
}
netlink_table_ungrab();
return sk;
out_sock_release:
kfree(listeners);
netlink_kernel_release(sk);
return NULL;
out_sock_release_nosk:
sock_release(sock);
return NULL;
}
EXPORT_SYMBOL(__netlink_kernel_create);
void
netlink_kernel_release(struct sock *sk)
{
sk_release_kernel(sk);
}
EXPORT_SYMBOL(netlink_kernel_release);
int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
{
struct listeners *new, *old;
struct netlink_table *tbl = &nl_table[sk->sk_protocol];
if (groups < 32)
groups = 32;
if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
if (!new)
return -ENOMEM;
old = nl_deref_protected(tbl->listeners);
memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
rcu_assign_pointer(tbl->listeners, new);
kfree_rcu(old, rcu);
}
tbl->groups = groups;
return 0;
}
/**
* netlink_change_ngroups - change number of multicast groups
*
* This changes the number of multicast groups that are available
* on a certain netlink family. Note that it is not possible to
* change the number of groups to below 32. Also note that it does
* not implicitly call netlink_clear_multicast_users() when the
* number of groups is reduced.
*
* @sk: The kernel netlink socket, as returned by netlink_kernel_create().
* @groups: The new number of groups.
*/
int netlink_change_ngroups(struct sock *sk, unsigned int groups)
{
int err;
netlink_table_grab();
err = __netlink_change_ngroups(sk, groups);
netlink_table_ungrab();
return err;
}
void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
{
struct sock *sk;
struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
sk_for_each_bound(sk, &tbl->mc_list)
netlink_update_socket_mc(nlk_sk(sk), group, 0);
}
struct nlmsghdr *
__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
{
struct nlmsghdr *nlh;
int size = nlmsg_msg_size(len);
nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
nlh->nlmsg_type = type;
nlh->nlmsg_len = size;
nlh->nlmsg_flags = flags;
nlh->nlmsg_pid = portid;
nlh->nlmsg_seq = seq;
if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
return nlh;
}
EXPORT_SYMBOL(__nlmsg_put);
/*
* It looks a bit ugly.
* It would be better to create kernel thread.
*/
static int netlink_dump(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_callback *cb;
struct sk_buff *skb = NULL;
struct nlmsghdr *nlh;
int len, err = -ENOBUFS;
int alloc_size;
mutex_lock(nlk->cb_mutex);
if (!nlk->cb_running) {
err = -EINVAL;
goto errout_skb;
}
cb = &nlk->cb;
alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
if (!netlink_rx_is_mmaped(sk) &&
atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
goto errout_skb;
/* NLMSG_GOODSIZE is small to avoid high order allocations being
* required, but it makes sense to _attempt_ a 16K bytes allocation
* to reduce number of system calls on dump operations, if user
* ever provided a big enough buffer.
*/
if (alloc_size < nlk->max_recvmsg_len) {
skb = netlink_alloc_skb(sk,
nlk->max_recvmsg_len,
nlk->portid,
GFP_KERNEL |
__GFP_NOWARN |
__GFP_NORETRY);
/* available room should be exact amount to avoid MSG_TRUNC */
if (skb)
skb_reserve(skb, skb_tailroom(skb) -
nlk->max_recvmsg_len);
}
if (!skb)
skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
GFP_KERNEL);
if (!skb)
goto errout_skb;
netlink_skb_set_owner_r(skb, sk);
len = cb->dump(skb, cb);
if (len > 0) {
mutex_unlock(nlk->cb_mutex);
if (sk_filter(sk, skb))
kfree_skb(skb);
else
__netlink_sendskb(sk, skb);
return 0;
}
nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
if (!nlh)
goto errout_skb;
nl_dump_check_consistent(cb, nlh);
memcpy(nlmsg_data(nlh), &len, sizeof(len));
if (sk_filter(sk, skb))
kfree_skb(skb);
else
__netlink_sendskb(sk, skb);
if (cb->done)
cb->done(cb);
nlk->cb_running = false;
mutex_unlock(nlk->cb_mutex);
module_put(cb->module);
consume_skb(cb->skb);
return 0;
errout_skb:
mutex_unlock(nlk->cb_mutex);
kfree_skb(skb);
return err;
}
int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
const struct nlmsghdr *nlh,
struct netlink_dump_control *control)
{
struct netlink_callback *cb;
struct sock *sk;
struct netlink_sock *nlk;
int ret;
/* Memory mapped dump requests need to be copied to avoid looping
* on the pending state in netlink_mmap_sendmsg() while the CB hold
* a reference to the skb.
*/
if (netlink_skb_is_mmaped(skb)) {
skb = skb_copy(skb, GFP_KERNEL);
if (skb == NULL)
return -ENOBUFS;
} else
atomic_inc(&skb->users);
sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
if (sk == NULL) {
ret = -ECONNREFUSED;
goto error_free;
}
nlk = nlk_sk(sk);
mutex_lock(nlk->cb_mutex);
/* A dump is in progress... */
if (nlk->cb_running) {
ret = -EBUSY;
goto error_unlock;
}
/* add reference of module which cb->dump belongs to */
if (!try_module_get(control->module)) {
ret = -EPROTONOSUPPORT;
goto error_unlock;
}
cb = &nlk->cb;
memset(cb, 0, sizeof(*cb));
cb->dump = control->dump;
cb->done = control->done;
cb->nlh = nlh;
cb->data = control->data;
cb->module = control->module;
cb->min_dump_alloc = control->min_dump_alloc;
cb->skb = skb;
nlk->cb_running = true;
mutex_unlock(nlk->cb_mutex);
ret = netlink_dump(sk);
sock_put(sk);
if (ret)
return ret;
/* We successfully started a dump, by returning -EINTR we
* signal not to send ACK even if it was requested.
*/
return -EINTR;
error_unlock:
sock_put(sk);
mutex_unlock(nlk->cb_mutex);
error_free:
kfree_skb(skb);
return ret;
}
EXPORT_SYMBOL(__netlink_dump_start);
void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
{
struct sk_buff *skb;
struct nlmsghdr *rep;
struct nlmsgerr *errmsg;
size_t payload = sizeof(*errmsg);
/* error messages get the original request appened */
if (err)
payload += nlmsg_len(nlh);
skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
NETLINK_CB(in_skb).portid, GFP_KERNEL);
if (!skb) {
struct sock *sk;
sk = netlink_lookup(sock_net(in_skb->sk),
in_skb->sk->sk_protocol,
NETLINK_CB(in_skb).portid);
if (sk) {
sk->sk_err = ENOBUFS;
sk->sk_error_report(sk);
sock_put(sk);
}
return;
}
rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
NLMSG_ERROR, payload, 0);
errmsg = nlmsg_data(rep);
errmsg->error = err;
memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
}
EXPORT_SYMBOL(netlink_ack);
int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
struct nlmsghdr *))
{
struct nlmsghdr *nlh;
int err;
while (skb->len >= nlmsg_total_size(0)) {
int msglen;
nlh = nlmsg_hdr(skb);
err = 0;
if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
return 0;
/* Only requests are handled by the kernel */
if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
goto ack;
/* Skip control messages */
if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
goto ack;
err = cb(skb, nlh);
if (err == -EINTR)
goto skip;
ack:
if (nlh->nlmsg_flags & NLM_F_ACK || err)
netlink_ack(skb, nlh, err);
skip:
msglen = NLMSG_ALIGN(nlh->nlmsg_len);
if (msglen > skb->len)
msglen = skb->len;
skb_pull(skb, msglen);
}
return 0;
}
EXPORT_SYMBOL(netlink_rcv_skb);
/**
* nlmsg_notify - send a notification netlink message
* @sk: netlink socket to use
* @skb: notification message
* @portid: destination netlink portid for reports or 0
* @group: destination multicast group or 0
* @report: 1 to report back, 0 to disable
* @flags: allocation flags
*/
int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
unsigned int group, int report, gfp_t flags)
{
int err = 0;
if (group) {
int exclude_portid = 0;
if (report) {
atomic_inc(&skb->users);
exclude_portid = portid;
}
/* errors reported via destination sk->sk_err, but propagate
* delivery errors if NETLINK_BROADCAST_ERROR flag is set */
err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
}
if (report) {
int err2;
err2 = nlmsg_unicast(sk, skb, portid);
if (!err || err == -ESRCH)
err = err2;
}
return err;
}
EXPORT_SYMBOL(nlmsg_notify);
#ifdef CONFIG_PROC_FS
struct nl_seq_iter {
struct seq_net_private p;
int link;
int hash_idx;
};
static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
{
struct nl_seq_iter *iter = seq->private;
int i, j;
struct sock *s;
loff_t off = 0;
for (i = 0; i < MAX_LINKS; i++) {
struct nl_portid_hash *hash = &nl_table[i].hash;
for (j = 0; j <= hash->mask; j++) {
sk_for_each(s, &hash->table[j]) {
if (sock_net(s) != seq_file_net(seq))
continue;
if (off == pos) {
iter->link = i;
iter->hash_idx = j;
return s;
}
++off;
}
}
}
return NULL;
}
static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(nl_table_lock)
{
read_lock(&nl_table_lock);
return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}
static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct sock *s;
struct nl_seq_iter *iter;
struct net *net;
int i, j;
++*pos;
if (v == SEQ_START_TOKEN)
return netlink_seq_socket_idx(seq, 0);
net = seq_file_net(seq);
iter = seq->private;
s = v;
do {
s = sk_next(s);
} while (s && !nl_table[s->sk_protocol].compare(net, s));
if (s)
return s;
i = iter->link;
j = iter->hash_idx + 1;
do {
struct nl_portid_hash *hash = &nl_table[i].hash;
for (; j <= hash->mask; j++) {
s = sk_head(&hash->table[j]);
while (s && !nl_table[s->sk_protocol].compare(net, s))
s = sk_next(s);
if (s) {
iter->link = i;
iter->hash_idx = j;
return s;
}
}
j = 0;
} while (++i < MAX_LINKS);
return NULL;
}
static void netlink_seq_stop(struct seq_file *seq, void *v)
__releases(nl_table_lock)
{
read_unlock(&nl_table_lock);
}
static int netlink_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN) {
seq_puts(seq,
"sk Eth Pid Groups "
"Rmem Wmem Dump Locks Drops Inode\n");
} else {
struct sock *s = v;
struct netlink_sock *nlk = nlk_sk(s);
seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
s,
s->sk_protocol,
nlk->portid,
nlk->groups ? (u32)nlk->groups[0] : 0,
sk_rmem_alloc_get(s),
sk_wmem_alloc_get(s),
nlk->cb_running,
atomic_read(&s->sk_refcnt),
atomic_read(&s->sk_drops),
sock_i_ino(s)
);
}
return 0;
}
static const struct seq_operations netlink_seq_ops = {
.start = netlink_seq_start,
.next = netlink_seq_next,
.stop = netlink_seq_stop,
.show = netlink_seq_show,
};
static int netlink_seq_open(struct inode *inode, struct file *file)
{
return seq_open_net(inode, file, &netlink_seq_ops,
sizeof(struct nl_seq_iter));
}
static const struct file_operations netlink_seq_fops = {
.owner = THIS_MODULE,
.open = netlink_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_net,
};
#endif
int netlink_register_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&netlink_chain, nb);
}
EXPORT_SYMBOL(netlink_register_notifier);
int netlink_unregister_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&netlink_chain, nb);
}
EXPORT_SYMBOL(netlink_unregister_notifier);
static const struct proto_ops netlink_ops = {
.family = PF_NETLINK,
.owner = THIS_MODULE,
.release = netlink_release,
.bind = netlink_bind,
.connect = netlink_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = netlink_getname,
.poll = netlink_poll,
.ioctl = sock_no_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = netlink_setsockopt,
.getsockopt = netlink_getsockopt,
.sendmsg = netlink_sendmsg,
.recvmsg = netlink_recvmsg,
.mmap = netlink_mmap,
.sendpage = sock_no_sendpage,
};
static const struct net_proto_family netlink_family_ops = {
.family = PF_NETLINK,
.create = netlink_create,
.owner = THIS_MODULE, /* for consistency 8) */
};
static int __net_init netlink_net_init(struct net *net)
{
#ifdef CONFIG_PROC_FS
if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
return -ENOMEM;
#endif
return 0;
}
static void __net_exit netlink_net_exit(struct net *net)
{
#ifdef CONFIG_PROC_FS
remove_proc_entry("netlink", net->proc_net);
#endif
}
static void __init netlink_add_usersock_entry(void)
{
struct listeners *listeners;
int groups = 32;
listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
if (!listeners)
panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
netlink_table_grab();
nl_table[NETLINK_USERSOCK].groups = groups;
rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
nl_table[NETLINK_USERSOCK].registered = 1;
nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
netlink_table_ungrab();
}
static struct pernet_operations __net_initdata netlink_net_ops = {
.init = netlink_net_init,
.exit = netlink_net_exit,
};
static int __init netlink_proto_init(void)
{
int i;
unsigned long limit;
unsigned int order;
int err = proto_register(&netlink_proto, 0);
if (err != 0)
goto out;
BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
if (!nl_table)
goto panic;
if (totalram_pages >= (128 * 1024))
limit = totalram_pages >> (21 - PAGE_SHIFT);
else
limit = totalram_pages >> (23 - PAGE_SHIFT);
order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
limit = (1UL << order) / sizeof(struct hlist_head);
order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
for (i = 0; i < MAX_LINKS; i++) {
struct nl_portid_hash *hash = &nl_table[i].hash;
hash->table = nl_portid_hash_zalloc(1 * sizeof(*hash->table));
if (!hash->table) {
while (i-- > 0)
nl_portid_hash_free(nl_table[i].hash.table,
1 * sizeof(*hash->table));
kfree(nl_table);
goto panic;
}
hash->max_shift = order;
hash->shift = 0;
hash->mask = 0;
hash->rehash_time = jiffies;
nl_table[i].compare = netlink_compare;
}
INIT_LIST_HEAD(&netlink_tap_all);
netlink_add_usersock_entry();
sock_register(&netlink_family_ops);
register_pernet_subsys(&netlink_net_ops);
/* The netlink device handler may be needed early. */
rtnetlink_init();
out:
return err;
panic:
panic("netlink_init: Cannot allocate nl_table\n");
}
core_initcall(netlink_proto_init);
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